Science Headlines for February 20, 2009

Injections Of Licorice Ingredient Show Promise As Treatment For Cocaine Addiction

An ingredient in licorice shows promise as an antidote for the toxic effects of cocaine abuse, including deadly overdoses of the highly addictive drug, researchers are reporting.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

Genetics Research Sheds Light On Evolution Of The Human Diet

Diet -- and how it has shaped our genome -- occupies much of an evolutionary scientist's time. Scientist hav explored how diet holds keys to understanding who we are, how we live and form societies, and how we evolved from hunter-gatherers to agriculturists, all the way to modern urban dwellers.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

NASA's Kepler Mission To Seek Other Earths

NASA's Kepler spacecraft is ready to be moved to the launch pad and will soon begin a journey to search for worlds that could potentially host life. It is the first mission with the ability to find planets like Earth -- rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface. Liquid water is believed to be essential for the formation of life.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

Will Online Shopping Look Something Like Second Life In The Future?

For all of the conveniences of online shopping -- no crowds, easy parking, seemingly endless choices -- it can't always compete with the real thing. At least not yet. A marketing professor said consumers can expect that some of the disadvantages of online shopping will disappear as retailers adapt models from Second Life.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

Indoor Plants Can Reduce Formaldehyde Levels

The toxic gas formaldehyde is contained in building materials including carpeting, curtains, plywood, and adhesives. As it is emitted from these sources, it deteriorates the air quality, which can lead to "multiple chemical sensitivity" and "sick building syndrome," medical conditions with symptoms such as allergies, asthma and headaches. The prevalence of formaldehyde and other volatile organic compounds is greater in new construction. Researchers are studying the ability of plants to reduce formaldehyde levels in the air.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

Water Vapor Feedback Loop Will Cause Accelerated Global Warming, Professor Warns

Here's yet another reason to hate humidity: it expands global warming, says a professor of Atmospheric Sciences writing in the journal Science. He says that warming due to increases in greenhouse gases will lead to higher humidity in the atmosphere. And because water vapor itself is a greenhouse gas, this will cause additional warming.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 7:00 pm

Chewing Gum Helps Treat Hyperphosphatemia In Kidney Disease Patients

Chewing gum made with a phosphate-binding ingredient can help treat high phosphate levels in dialysis patients with chronic kidney disease, according to a new study. The results suggest that this simple measure could maintain proper phosphate levels and help prevent cardiovascular disease in these patients.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 4:00 pm

Soybean Product Fights Abnormal Protein Involved In Alzheimer’s Disease

A vegan food renowned in Asia for its ability to protect against heart attacks also shows a powerful ability in lab experiments to prevent formation of the clumps of tangled protein involved in Alzheimer's disease, scientists are reporting.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 4:00 pm

Shark Attacks Decline Worldwide In Midst Of Economic Recession

The recession may be responsible for a slump of a different sort: an unexpected dive in shark attacks, says a University of Florida researcher.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 4:00 pm

Fruit Flies Sick From Mating

Mating can be exhausting. When fruit flies mate, the females' genes are activated to roughly the same extent as when an immune reaction starts. Using a combination of behavioral studies and genomic technology, researchers in Sweden can show how fruit fly females are affected by mating.
Source: ScienceDaily: Latest Science News | 20 Feb 2009 | 4:00 pm

James Hansen's war on coal

The next time you hear someone say "we are addicted to oil" or "we are addicted to coal", try this exercise: substitute the word "prosperity" for "oil". Do the same for "coal".

This suggestion came to mind while reading James Hansen's latest broadside against coal. On 15 February, Hansen wrote an opinion piece for the Guardian, in which he declared: "Coal is the single greatest threat to civilisation and all life on our planet." In late December 2008, Hansen sent an open letter to Barack Obama and his wife, Michelle, in which he called coal-fired power plants "factories of death" (pdf).

Hansen justifies his campaign against coal because of his belief that a global climate catastrophe looms just ahead. Perhaps Hansen is right. Then again, it's also possible that he's wrong.

I no longer care about the scientific arguments about global warming. I've read what Al Gore has to say. I've seen his movie, An Inconvenient Truth. And I've seen a fair amount of what the so-called "sceptics" have to say. Again, I have no opinion on the merits of the science. The argument has gotten so shrill and divisive that I am bored by it. My position is this: how can the US and/or the EU tell the rest of the world not to use coal?

Sure, it's possible that the US (and maybe some members of the EU) could give up coal. That would mean a loss of about 50% of the electric generating capacity in the US. But that might be OK. Perhaps some Americans are bored with lights, refrigeration and climate-controlled houses.

There are two key problems with Hansen's argument against coal: cost and scale.

Hansen doesn't offer a single idea as to what the world will use to replace the coal that he abhors. Coal currently provides about 28% of the world's total energy use. And it is the cheapest source of fuel for electric power production. That's why developing countries – China and India in particular – are using so much of it.

Furthermore, the possible replacements for coal – wind and solar power in particular – are incurably intermittent and therefore cannot be used for baseload capacity. That means that barring a breakthrough technology in electricity storage, wind and solar are likely to contribute only small – that is, single-digit – percentages of our overall energy needs. (Lest readers think I am against renewables let me be clear: I've put my money into this technology. I have 3,200 watts of photovoltaic panels on my house here in Texas.)

Energy consumption creates wealth. It is axiomatic: As energy use rises, people get richer. And that's particularly true of electricity. Peter Huber and Mark Mills – in their outstanding 2005 book about energy, The Bottomless Well – made this point clear, declaring: "Economic growth marches hand in hand with increased consumption of electricity – always, everywhere, without significant exception in the annals of modern industrial history."

It is no accident that the countries with the highest per-capita incomes are also the ones with the highest rates of energy consumption. Nor is it accidental that many of the countries with the fastest-growing economies are also the ones that have done the most to boost their electricity generation capacity. Between 1990 and 2007, the five countries with the biggest increases in electricity generation were China, Indonesia, Malaysia, United Arab Emirates and South Korea.

The second problem with Hansen's prospective coal ban: scale. According to the latest data from the BP Statistical Review of World Energy, the countries of the world now consume the coal equivalent of about 63.8 million barrels of oil per day. That's the energy equivalent of about 7.5 times the daily oil production of Saudi Arabia. Where will the world find a replacement for such a vast quantity of energy? And how will it pay for it, particularly now, given the worldwide recession?

Hansen doesn't offer any ideas. And frankly, aside from a huge push for increased nuclear power (a move that I favour) no one else has any reasonable ideas either. That's why the world will continue using coal – and lots of it – for decades to come.

Perhaps the best argument against any effort to cut carbon dioxide levels (read: fossil fuel use) comes from Freeman Dyson, a renowned professor of physics at the Institute for Advanced Study at Princeton University. In August 2007, Dyson wrote an essay for Edge that forced me to change my thinking about energy use and climate issues. (For the record, Dyson is a sceptic on climate change. In his essay, he makes that clear: "My first heresy says that all the fuss about global warming is grossly exaggerated. Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the computer models.")

But the essence of Dyson's essay isn't about the science of global warming. Instead, it's about energy use and equity – and the need to keep those issues in mind when discussing climate change. "The greatest evils are poverty, underdevelopment, unemployment, disease and hunger, all the conditions that deprive people of opportunities and limit their freedoms," he wrote. "The humanist ethic accepts an increase of carbon dioxide in the atmosphere as a small price to pay, if worldwide industrial development can alleviate the miseries of the poorer half of humanity."

To that, I say amen.

The hard truth is that we will have to adapt to any changes in the world's climate – regardless of the causes of those changes. And the reason we will have to adapt is simple: we are addicted to prosperity.

guardian.co.uk © Guardian News & Media Limited 2009 | Use of this content is subject to our Terms & Conditions | More Feeds

Source: Evolution, genetics, medicine, physics & astronomy news | guardian.co.uk | 20 Feb 2009 | 1:00 pm

'Superguns' of Elizabeth I's navy

Elizabeth I's navy from around the time of the Armada was evolving into a far more powerful force than previously realised.
Source: BBC News | Science & Environment | UK Edition | 20 Feb 2009 | 11:59 am

Hurricane Season 2008 (weather.com)

weather.com -
Source: Yahoo! News: Science News | 20 Feb 2009 | 11:05 am

Telescope spies cataclysmic blast

Nasa's Fermi Gamma-ray Space Telescope records the most powerful radiation blast from deep space yet detected.
Source: BBC News | Science & Environment | UK Edition | 20 Feb 2009 | 10:37 am

National Guard goes green to conserve energy, cost (AP)

AP - The rapid whop, whop, whop of a wind turbine outside the New Mexico National Guard headquarters hints at a new mission for the homefront military: Going green.

Source: Yahoo! News: Science News | 20 Feb 2009 | 10:02 am

NASA readies mission to find Earth-like planets (AFP)

AFP - NASA is preparing to launch next month the Kepler spacecraft with a new space telescope that for the first time will be capable of detecting Earth-like planets outside our solar system, project managers said.

Source: Yahoo! News: Science News | 20 Feb 2009 | 6:37 am

Scientists make advances on "nano" electronics

CHICAGO (Reuters) - Two U.S. teams have developed new materials that may pave the way for ever smaller, faster and more powerful electronics as current semiconductor technology begins to reach the limits of miniaturization.

Source: Reuters: Science News | 20 Feb 2009 | 4:51 am

Chile's Chaiten volcano spews molten rock, ash

SANTIAGO (Reuters) - Chile's Chaiten volcano, which erupted spectacularly last year, spewed a vast cloud of ash as well as gas and molten rock on Thursday in a partial collapse of its cone, prompting a fresh evacuation.

Source: Reuters: Science News | 20 Feb 2009 | 2:25 am

Dinosaurs Needed More Than Feathers to Fly

Flashy feathers get all the attention in the evolution of dinosaur flight, but a more complex internal adaptation provided the aerodynamics necessary for lizards to go airborne.

Fossil analysis suggests that pterosaurs had sacs of air in their bodies, starting in their lungs and spreading beyond, even hollowing out their bones. They were, in short, not nearly as heavy as their size suggested.

"We offer a reconstruction of the breathing system in pterosaurs, one that proposes the existence of a mechanism with the same essential structure to that of modern birds — except 70 million years earlier," study co-author Leon Claessens, a biologist at College of the Holy Cross, said in a press release.

The findings, published Thursday in Public Library of Science ONE, answer a lingering mystery: pterosaur skeletons have features suggestive of wing flapping, but the energy necessary to keep such heavy bodies in flight would have been huge.

Claessens' team couldn't look at fossilization-unfriendly soft tissue, but instead compared the skeletons of large modern birds and pterosaurs. Using x-ray movies and CT scans, they charted the skeletal mechanics of wing flapping in birds, then found similar bone structures in the dinosaurs. They also observed nearly identical relationships between body size and bone density.

Without internal balloons and hollow bones, dinosaurs couldn't have flown, much less reached sizes comparable to small airplanes. Fortunately for humans, however, birds have followed an evolutionary path less prone to gigantism.

After all, who'd want to deal with Cessna-sized pigeons?

Citation: "Respiratory Evolution Facilitated the Origin of Pterosaur Flight and Aerial Gigantism." By Leon P. A. M. Claessens, Patrick M. O'Connor, David M. Unwin. Public Library of Science ONE, Feb. 18, 2009.

Images: PLoS ONE

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Brandon Keim's Twitter stream and Del.icio.us feed; Wired Science on Facebook.

Source: Wired: Wired Science | 20 Feb 2009 | 1:26 am

Hope over peanut allergy 'cure'

A group of children with peanut allergies have had their condition cured after being desensitised, doctors believe.
Source: BBC News | Science & Environment | UK Edition | 20 Feb 2009 | 12:41 am

Cure for nut allergies moves a step closer

Scientists are one step closer to curing severe nut allergies that affect thousands of people across the UK, according to research published today.

Doctors at Addenbrooke's hospital in Cambridge said they had developed a successful desensitisation programme which builds up tolerance in patients by slowly exposing them to tiny doses of peanut.

Four children who took part in the trial, which is published in the Allergy medical journal, were fed minute doses of peanut flour over six months. Researchers said the children, who risked fatal anaphylactic shock from contact with traces of peanut, were started on an initial dose of 5mg but by the end were able to tolerate 880mg - the equivalent of five peanuts.

Dr Andy Clark, who led the research, said: "Every time people with a peanut allergy eat something, they're frightened that it might kill them. Our motivation was to find a treatment that would change that and give them the confidence to eat what they like."

He said peanut allergy affected one in 50 young people in the UK. "Unlike other childhood food allergies like cow's milk, it rarely goes away," he said. "For all our participants, a reaction could lead to life-threatening anaphylactic shock - but now we've got them to a point where they can safely eat up to 10 whole peanuts or more. It's not a permanent cure, but as long as they go on taking a daily dose they should maintain their tolerance."

Kate Frost, whose nine-year-old son Michael had suffered non-stop vomiting and hives from a 16th of a nut, said the family were "over the moon" at the results of the trial at the Wellcome Trust clinical research facility. "It's hard to describe how much of a difference it's made. I feel I've been playing Russian roulette with my child's life. It's absolutely fantastic."

guardian.co.uk © Guardian News & Media Limited 2009 | Use of this content is subject to our Terms & Conditions | More Feeds

Source: Evolution, genetics, medicine, physics & astronomy news | guardian.co.uk | 20 Feb 2009 | 12:01 am

To understand economics, we have to consider emotions too

Larry Elliott is right to emphasise that economics cannot be reduced to mechanisms operated by rationally thinking people We are on the brink - perhaps it is time to look to the Romantics for what lies ahead, 16 February). As he notes: "All the fancy models purporting to show only a minuscule risk of financial blow-out were flawed. They assumed the complexity could be captured by mathematics and pseudo-science."

The article invites us to turn to the Romantics and to Richard Bronk's new book The Romantic Economist. Bronk is quoted: "Standard economics assumes that economic agents are perfectly rational; that is the basis of its predictive equilibrium-based models."

We should also consider the place of emotions in economic life. The share price of UK banks fluctuates wildly as traders attempt to calculate their capital value from future estimated losses and profits. Keynes, in 1933 in his lectures on his General Theory, said that current yields of firms exercise an "irrational" influence on estimating future worth.

Nobody can predict the future earning power (or losses) of giant banking groups. In a climate of fear, where uncertainty is high, the share price is marked down, just as two years ago in a climate of greed the share price of banks was marked up too highly. Because the future is inherently uncertain, emotion and sentiment will drive all manner of behaviour. The extent of the downturn cannot be predicted, as Elliott notes of Mervyn King's latest Bank of England inflation report, because "animal spirits were currently depressed".

According to Frank Partnoy - the former derivatives trader turned academic - the dominant emotion of the finance-led boom was "infectious greed". Infectious greed and optimism was the mindset of economists, bankers, politicians and regulators - leading to behaviour that no regulatory mechanism could have controlled. But the extent of the greed and adventurism, and the flouting of standard banking precautions which had been stress-tested by decades of history, raises the question of what determines which emotions come to the fore.

One theorist not mentioned by Elliott is Max Weber, who pointed out that the capitalist spirit is not reducible to economics alone. Rational sober conduct on the part of early capitalists was determined by a Puritan and ever-present fear of damnation. Such attitudes would no doubt make the job of the FSA far easier, but the business class have long since gone beyond Puritan values.

Over the last decade Anglo-Saxon attitudes have been dominated by what Weber would have called the values of adventurer capitalism, and the economist and sociologist Werner Sombart would have called the lust for wealth. Meanwhile we have been duped into believing that whatever happens in the marketplace is for the best of all possible worlds.

Aesthetics, harmony with nature, the ethics and politics of community - these need to be reasserted as values independent of and superior to market values, which as the Romantics pointed out should be merely means to other ends. It is time for what Nietzsche termed the revaluation of values. As part of this process the Global Policy Institute (global-policy.com) is organising conferences on the return of the state and what we should now expect from bankers and financiers.

• Sam Whimster is professor of sociology in the Global Policy Institute s.whimster@londonmet.ac.uk

guardian.co.uk © Guardian News & Media Limited 2009 | Use of this content is subject to our Terms & Conditions | More Feeds

Source: Evolution, genetics, medicine, physics & astronomy news | guardian.co.uk | 20 Feb 2009 | 12:01 am

Economic Recession Means Fewer Shark Attacks (LiveScience.com)

LiveScience.com - Shark attacks are on the decline due to the current economic downturn, a biologist speculated today.

Source: Yahoo! News: Science News | 19 Feb 2009 | 10:56 pm

Economic Recession Means Fewer Shark Attacks

Tighter budgets mean fewer trips to the beach and less chances to get bit by a shark.
Source: Livescience.com | 19 Feb 2009 | 9:36 pm

NASA spacecraft to seek out Earth-like planets

WASHINGTON (Reuters) - A U.S. spacecraft toting the biggest camera ever sent into space will be launched next month to scour our region of the Milky Way galaxy for warm, rocky planets like Earth that may host life, NASA said on Thursday.

Source: Reuters: Science News | 19 Feb 2009 | 9:00 pm

What a mess! Experts ponder space junk problem (AP)

AP - Think of it as a galactic garbage dump. With a recent satellite collision still fresh on minds, participants at a meeting in the Austrian capital this week are discussing ways to deal with space debris junk that is clogging up the orbit around the Earth.

Source: Yahoo! News: Science News | 19 Feb 2009 | 8:53 pm

Brightest-Ever Gamma Ray Burst Spotted

An explosion in the Carina constellation is the biggest gamma ray burst ever seen, say scientists.
Source: Discovery News Top Stories : Discovery Channel | 19 Feb 2009 | 8:45 pm

NASA Creating Online Multiplayer Video Game

NASA chooses three game developers to create its online multiplayer game.
Source: Livescience.com | 19 Feb 2009 | 8:43 pm

150 dogs, tiger rescued from Missouri dog breeder (AP)

AP - The Humane Society of Missouri says it rescued more than 150 dogs and a Bengal tiger from a substandard dog breeder near Seneca.
Source: Yahoo! News: Science News | 19 Feb 2009 | 8:20 pm

Out There: Billions and Billions of Habitable Planets

There are about ten thousand billion billion habitable planets in the observable universe, and some of these Earth-like worlds could be found soon.
Source: Livescience.com | 19 Feb 2009 | 8:16 pm

Ancient Black Sea Flood: Nuisance or Calamity?

Was the flooding of the Black Sea 9,500 years ago of biblical proportions?
Source: Discovery News Top Stories : Discovery Channel | 19 Feb 2009 | 8:16 pm

Scientists find genes to protect wheat from rust

LONDON (Reuters) - Scientists have pinpointed two genes that protect wheat against devastating fungal diseases found worldwide, potentially paving the way to hardier wheat strains, international researchers reported on Thursday.

Source: Reuters: Science News | 19 Feb 2009 | 7:06 pm

Scientists find genes to protect wheat from rust (Reuters)

Reuters - Scientists have pinpointed two genes that protect wheat against devastating fungal diseases found worldwide, potentially paving the way to hardier wheat strains, international researchers reported on Thursday.

Source: Yahoo! News: Science News | 19 Feb 2009 | 7:06 pm

100-Foot 'Borneo Monster' Said Photographed

A legendary snake-like creature is thought to have come alive.
Source: Livescience.com | 19 Feb 2009 | 6:55 pm

Value of Brain Exercises Questioned

Crossword puzzles, crafts and other stimulations decrease dementia but are they just markers of a healthy lifestyle?
Source: Livescience.com | 19 Feb 2009 | 6:27 pm

New Clues for Anti-Aging Therapy

New insights into how cells cope with stress could help combat neurological diseases and reduce the ravages of aging.

Scientists have known for years that moderate stressors, such as a calorie-restricted diet, increase lifespan in a variety of organisms. Now new research is illuminating how this works at the molecular level. A particular protein is key in regulating at least one aspect of the stress response and may be a good model for anti-aging drugs.

"What we have here is an essential protective pathway that now looks like a very effective therapeutic target," said biologist Richard Morimoto of Northwestern University.

Most research on this protein, called sirtuin1 (SIRT1), has concentrated on its ability to regulate and protect mitochondria — cellular power generators that are corroded over time by reactive oxygen molecules. But SIRT1 also protects DNA in the cell nucleus. Morimoto's findings, published Thursday in Science, give a precise mechanical explanation for the effects.

Cells have evolved a particular response to stay alive in adverse conditions. When a cell starts getting too hot, too hungry or too oxygen-deprived, certain proteins migrate into the nucleus. There, they latch onto sections of DNA and cause heat-shock proteins to be produced. Heat-shock proteins — so named because they were first discovered in cells experiencing high temperatures — cruise around the cell, fixing damaged or improperly folded proteins.

"Proteins are very delicate," Morimoto said. "Any change in the environment causes them to misfold."

Repairing proteins keeps cells, and the body, in top shape. Animals exposed to only minor stresses — such as a calorie-restricted diet — reap the benefits and live longer.

"A little stress is good," said lead author Sandy Westerheide, also of Northwestern. "You don't want to overdo it, though."

Normally the repair process falls off quickly, because heat-shock proteins inhibit the proteins that grab onto the cell's DNA and summon them in the first place. But Morimoto and his colleagues found that jacking up levels of SIRT1 keeps the protein-repair process going for hours and hours.

SIRT1 helps recruit at least one of the summoner proteins to its proper place on the cell's DNA. And the compound has direct survival benefits. The researchers subjected normal cells and those with high SIRT1 levels to temperatures of 115 degrees Fahrenheit. Compared to the control group, only one-third as many high-SIRT1 cells died.

"The results support the idea that low levels of stressors influence lifespan and provide additional potential molecular targets that can be further manipulated experimentally or therapeutically," write biologists Laura Saunders and Eric Verdin in an accompanying review paper in Science.

Westerheide said the team is indeed screening molecules for promising medical potential. Now that they know more about how the stress pathway works, finding or designing a drug to boost SIRT1 levels is more feasible.

Another option is finding something that makes SIRT1 more efficient inside the cell. In the study, Westerheide and her colleagues used the compound resveratrol, which occurs naturally in red wine, to this effect. Other researchers have linked resveratrol to extended lifespan in yeast, worms, fruit flies, fish and mice. The compound occurs naturally in red wine, but probably not in high enough concentrations to have an appreciable effect on human health. Researchers are working to synthesize more potent compounds that have the same effect as resveratrol.

A drug modeled on the SIRT1 pathway could also help treat currently incurable neurological diseases such as Alzheimer's, Parkinson's and Lou Gehrig's disease, Morimoto said.

"These are all protein-misfolding diseases, diseases of aging," he said. "For neurodegeneration, there's nothing that can be done right now."

The study will also give more confidence to people who are trying to extend their lives by severely restricting their food intake. Such extreme dieting, popularized by the late Roy Walford, has grown into a movement.

"I'm not going to get on the diet-restriction bandwagon," Morimoto said. "But a little less consumption would be good for us. If you fast for 12 hours, that's enough to send the right signals to your system."

Citation: "Stress-Inducible Regulation of Heat Shock Factor 1 by the Deacetylase SIRT1." By Sandy D. Westerheide, Julius Anckar, Stanley M. Stevens Jr., Lea Sistonen, Richard I. Morimoto. Science Vol. 323, 20 February 2009.

See Also:

Image: Flickr/Prakhar

Source: Wired: Wired Science | 19 Feb 2009 | 6:00 pm

After You Die, Your Data Lives On

Watch what can transpire - after you expire - if you don't leave your login info for your loved ones. Your final words should actually be your passwords. Account access after death is tricky.
Source: Livescience.com | 19 Feb 2009 | 5:54 pm

Milky Way 'Ringing' Caused by Galaxy Crash

Our galaxy still rings after colliding with another galaxy two billion years ago.
Source: Discovery News Top Stories : Discovery Channel | 19 Feb 2009 | 5:45 pm

Scientists Exploit Bacterial Laziness to Beat Disease

Infectious diseases may have an unexpected weakness: their own propensity for laziness.

Researchers genetically engineered "cheating" versions of a common, inflammation-causing microbe. When injected into already-infected mice, the bugs benefited from the chemical labors of other microbes without working themselves.

Able to devote their energies to reproduction, the lazy bugs divided faster than their brethren, and infections turned rapidly less virulent.

"The wild bacteria expend all this energy to make these signaling compounds and virulence factors. That slows down their growth," said Kendra Rumbaugh, a microbiologist at Texas Technical University and lead author of the study, published Thursday in Current Biology. "The cheaters save up like crazy, divide like crazy, and take over the population."

When bacteria invade a host, they exchange chemical signals that activate genes responsible for producing virulence factors — toxic molecules that break down connective tissue, stop cellular defenses and wreak cell-level havoc, creating an environment in which the bacteria can flourish.

Earlier research found that some microbes don't participate in the signaling. Since then, researchers have shown that these freeloaders flourish, at least in laboratory tissue cultures, where they outcompete hard-working bugs and produce less-virulent colonies. Rumbaugh wondered whether the same would happen in an actual infection.

The results, though still preliminary — they involved just one type of infection, observed in a mouse model — suggest that bacterial laziness could be a back-door approach for treating disease, especially drug-resistant strains.

"I like the analogy of cheaters as bacteria who don't pay their taxes," said Rumbaugh. "We all pay taxes, that gets us services and infrastructure. But there's a few people in the population that don't pay, yet they still use these. What happens if cheaters grow to be the majority of the population? Eventually, the society is going to collapse."

To test their hypothesis, Rumbaugh's team engineered a mutant strain of Pseudomonas aeruginosa, a common inflammation-causing bug that infects cuts and open wounds, and is especially troublesome for burn victims and people with AIDS. Though it usually causes dermatitis, P. aeruginosa can be fatal if infection spreads internally.

The researchers knocked out the genes responsible for signaling, turning their bugs into cheaters. Then they added the mutants to mice with burn wounds infected by normal P. aeuruginosa. The engineered strain flourished and soon dominated the bacterial population. More than half of treated mice survived, compared to just one-quarter of an untreated control group.

"These wild bacteria make chemical signals, turning on genes, making proteins, expending energy. There's a significant cost, but a benefit for the whole population," said Rumbaugh. "The cheaters don't make these signals, or all the things controlled by signaling. They just live off what the majority of the population is making."

Rumbaugh hopes the technique could eventually treat infections, especially those resistant to drugs. "We could take an attenuated mutant cheater strain and spike the population," she said. "It would predominate, and maybe make them more susceptible to treatment."

However, she noted that such treatments are still "far off," a caution echoed by Harvard University systems biologist Kevin Foster.

Rumbaugh's laziness hack could work, he said, but several caveats first need to be addressed. "The idea of introducing more bacteria — even less-virulent ones — to a patient comes with obvious potential side effects, because you have to increase the total number of pathogens in a patient," said Foster, who was not involved in the study.

Other strains of bacteria may also react unpredictably to the mutants. "The modified strain could make things worse," he said.

Citation: "Quorum Sensing and the Social Evolution of Bacterial Virulence." By Kendra Rumbaugh, Stephen Diggle, Chase Watters, Adin Ross-Gillespie, Ashleigh Griffin and Stuart West. Current Biology, Vol. 19, Iss. 4, Feb. 19, 2009.

Image: WikiMedia Commons

See Also:

Brandon Keim's Twitter stream and Del.icio.us feed; Wired Science on Facebook.

Source: Wired: Wired Science | 19 Feb 2009 | 5:00 pm

Climate change (19th century style)

A hundred and fifty years ago today a gifted child called Svante Arrhenius was born in the Uppsala region of Sweden. Self-taught in reading and arithmetic by the age of three – or so it is said – young Svante went on to study at the Swedish Academy of Sciences, where his dissertation included more than fifty original theses and the seed of work that would later win him a Nobel Prize for Chemistry. (The dissertation received a third-class mark, nonetheless, so maybe there's hope for the rest of us yet.)

Among Arrhenius's most important scientific achievements was an 1896 paper entitled On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground. Published in Philosophical Magazine, this paper pinned down the workings of the greenhouse effect and laid the scientific basis for the emissions cuts being debated to this day.

Earlier figures such as Joseph Fournier and John Tyndall had suspected the air warmed the earth by absorbing infrared energy. In the words of Tyndall, seemingly a scientist who harboured literary ambitions, the atmosphere "is a blanket more necessary to the vegetable life of England than clothing is to man. Remove for a single summer-night the aqueous vapour from the air … and the sun would rise upon an island held fast in the iron grip of frost."

Arrhenius took the science to a whole new level by showing that the power of the atmosphere's warming effect was determined by the amount of carbonic acid (CO2) it contained. He predicted that if the amount of CO2 in the atmosphere doubled, then the temperature would rise by around 5–6 degrees – not a world away from today's figure of 2–4.5 degrees.

It took a huge amount of work to reach this conclusion, but Arrhenius knew he was fighting an important scientific battle. "I should certainly not have undertaken these tedious calculations if an extraordinary interest had not been connected with them", he barked in the paper.

Arrhenius was well aware of one of the key implications of his research: that the burning of fossil fuels was likely to warm the planet. However, partly because he had no way to predict the meteoric rise in global fossil fuel consumption over the following hundred years, he wasn't worried about the possibility that man-made global warming might rapidly render the planet uninhabitable. On the contrary, he was optimistic that it might prove helpful by delaying the next ice age.

So Arrhenius didn't get everything right. And his involvement in "racial biology" – which blazed a trail for compulsory sterilization and eventually Nazi eugenics – doesn't help his legacy.

Nonetheless, the world should be grateful for the insights of this remarkable man, not least because he made his key contribution to science at considerable personal expense. As Rob Kunzig writes in Fixing Climate, Arrhenius's "ravishing young wife", Sophia, left him in 1894, half way through his greenhouse number crunching. Clearly Svante wasn't the only one who found his calculations tedious.

guardian.co.uk © Guardian News & Media Limited 2009 | Use of this content is subject to our Terms & Conditions | More Feeds

Source: Evolution, genetics, medicine, physics & astronomy news | guardian.co.uk | 19 Feb 2009 | 4:09 pm

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